Digital television enables network service providers to offer many new capabilities and services. For example, modern video compression/decompression algorithms (codecs) enable many digital channels to be squeezed into bandwidth that is otherwise consumed by only a few analog channels. Additionally, using digital media streams facilitates the offering of video-on-demand (VOD) programs. Digital media streams also facilitate the inclusion of other related data along with the television signal transmission. The other related data may be used to offer additional interactive services.
However, digital television suffers from one drawback that frustrates many customers and therefore concerns industry players. Changing channels is usually much slower with digital television as compared to traditional analog television. Analog channel changes, which often take 300-500 milliseconds (ms), are generally interpreted by viewers to be essentially instantaneous. Digital channel changes, on the other hand, are usually not interpreted to be instantaneous.
Many current users of digital television are familiar with the black screen that greets them for a number of seconds as they switch to a new digital channel. In fact, channel changes with digital television can take several seconds (e.g., up to 3-5 seconds) with current codecs. Although future codecs will likely consume significantly less bandwidth than current ones, these future codecs may very well stretch this channel-changing delay to a seemingly unacceptable period of over 10 seconds.